Factors inhibiting parathion hydrolysis in organic matter-amended soil under flooded conditions

Summary A water-extractable factor that developed in a flooded soil amended with 0.5% glucose or rice straw inhibited the biological hydrolysis of parathion. In glucose-amended flooded soil, the factor was removed by filtration of the standing water through a Millipore filter. Apparently, glucose application enhanced the proliferation of micro-organisms detrimental to parathionhydrolyzing agents. On the other hand, the toxic factor formed in rice straw-amended soil under flooded conditions passed through a Millipore membrane and was not inactivated by steam treatment. The toxicity developed within 36 h after flooding of rice straw-amended soil and persisted for 90 days or more under continued flooding. These studies indicated that a heat-resistant and stable factor with ability to block the hydrolysis of parathion developed in rice straw-amended soil under flooded conditions.